Schizosaccharomyces pombe Rho GTPases regulate actin cytoskeleton organization and cell integrity. We studied the
fission yeast gene SPBC4F6.12 based on its ability to suppress the thermosensitivity of cdc42-1625 mutant strain. This
gene, named pxl1 , encodes a protein with three LIM domains that is similar to paxillin. Pxl1 does not interact with Cdc42
but it interacts with Rho1, and it negatively regulates this GTPase. Fission yeast Pxl1 forms a contractile ring in the cell
division region and deletion of pxl1 causes a delay in cell– cell separation, suggesting that it has a function in cytokinesis.
Pxl1 N-terminal region is required and sufficient for its localization to the medial ring, whereas the LIM domains are
necessary for its function. Pxl1 localization requires actin polymerization and the actomyosin ring, but it is independent
of the septation initiation network (SIN) function. Moreover, Pxl1 colocalizes and interacts with Myo2, and Cdc15,
suggesting that it is part of the actomyosin ring. Here, we show that in cells lacking Pxl1, the myosin ring is not correctly
assembled and that actomyosin ring contraction is delayed. Together, these data suggest that Pxl1 modulates Rho1 GTPase
signaling and plays a role in the formation and contraction of the actomyosin ring during cytokinesis.